Intercommunicating gangways between two consecutive platforms supported by one or more wheeled bases have been developed for passenger transport and also for transporting merchandise, particularly road vehicles and other motorized loads on wheels or merchandise to be moved, lifted or displaced by handling devices on wheels during loading and unloading operations.
To facilitate loading and unloading operations, it is very desirable to be able to circulate from one platform to another without the need to descend from the wheeled base upon reaching the end, only to then ascend the next platform.
The existence of intercommunicating gangways between platforms also reduces the number of access ramps or handling and lifting means required, since they are needed only for the two wheeled bases located at the ends of the convoy.
However, the presence of these intercommunicating gangways must not cause any problems while the convoy of bodies on wheeled bases is moving. During travel, the space between the opposing extremities of two consecutive platforms of two consecutive wheeled bases undergoes significant changes with regard to both dimension and shape due to the topology of the route or variations in driving, for example, when taking curves, moving over depressed or raised surfaces or slopes, or because of braking, acceleration or jolting.
The intercommunicating gangways must be able to adapt easily to these variations or deformations in the space between platforms without causing any difficulties during travel.
The problem is further complicated when the height or angle of the plates or platforms relative to one another varies, which is the case, for example, with wheeled bases supporting loading platforms for vehicle transport.
Intercommunicating gangways for passengers are quite specialized, as they require overhead protection to seal off the assemblies from the outside environment.
Insofar as merchandise is concerned, this protection is needed only rarely or not at all, as the merchandise is individually protected. This is especially true when transporting vehicles. In this instance, intercommunicating gangways developed by the prior art conventionally consist of a connecting structure between the two opposing transverse edges of two consecutive platforms or plates.
The simplest and most current prior art construction uses pivoting connecting flaps. These pivoting flaps, which are two in number, when folded and deployed, serve as the intercommunicating connection between consecutive plates. Each flap has one end that is attached either to or near the transverse end edge of one plate and pivots, and another end that rests after pivoting on a contact area near the opposing transverse end edge of the successive plate. The flaps are each articulated to an opposing transverse end edge so as to constitute a passageway between two folding deployable elements.
When the loading and unloading operations are complete, these flaps must be manually folded back onto the platform they are connected to so they do not interfere with travel.
Despite being particularly simple, this passageway structure is not without various drawbacks. The principal one is the necessity for the operator to deploy and then fold up the various flaps on the intercommunicating passageways; an oversight on the operator's part could cause damage to the flaps or the end of the plate during travel.
Moreover, this structure is only used during loading and unloading operations. During travel it is impossible to leave cargo such as, for example, a vehicle, on this structure, with one portion on one of the plates and another portion on the other plate.
Additionally, plates of adjustable height or angle present another risk when different adjustments are made on two successive plates.
When the flaps are deployed, wide amplitude movements between the two successive plates joined in this way, especially during positioning and adjustment maneuvers may cause the flaps to disconnect.
When the end of one of the plates rises, the folded flap connected to the other plate begins to lift up, then finally falls flat if the motion continues. It then becomes an obstacle to the upper platform returning to its initial, or lower, position and there is a risk it will be damaged.
Obviously, operators take care to avoid breakage. They supervise maneuvers throughout the entire process of positioning the plates during the loading and unloading preceding or following the transportation phase, and they proceed to deploy and fold the flaps as necessary. However, the possibility of an oversight cannot be completely eliminated.